In hammer driven firearm trigger assemblies or fire control systems, such as for handguns, shotguns and various other types of long guns including lever action and semiautomatic rifles, the hammer of the firearm generally is held in a cocked position by a mechanical interface with a sear. The sear is connected either directly or through mechanical linkages to the trigger of the firearm. When the trigger is squeezed or moved rearward to fire a round of ammunition, the sear generally is moved out of locking engagement with the hammer so as to release the hammer. The hammer then is pivoted into contact with a firing pin of the firearm by a hammer spring. The engagement of the firing pin by the hammer causes the firing pin to strike a round of ammunition in the chamber of the firearm to initiate the firing of a round of ammunition.
FIG. 1 generally illustrates a conventional hammer sear interface in which the sear 2 includes a notched, hooked portion 6 that engages a corresponding notch or hook 8 formed in the rear hammer 4. Due to the sliding nature of this mechanical interface, the sear 2 and hammer 4 generally must be precisely machined so as to provide and ensure smooth and even surfaces on both the hammer and sear, so as to provide a smooth and crisp trigger feel during shooting to avoid catching or hesitation during firing, which can lead to misfires and affect the aim of the shooter. In addition, it is also important for hammer/sear interfaces that upon a partial trigger pull, i.e., where the sear 2 is partially rotated but does not release the hammer 4, the two components must be returned to full engagement upon release of the trigger to prevent inadvertent discharge of the firearm. The critically of the components returning to full engagement upon release of the trigger thus further requires that the geometry and surface finishes of the hammer 4 and sear 2 be carefully and precisely machined and finished, such that the hammer and sear will regain full engagement in such a situation in which the trigger is released after a partial trigger pull without firing. Such precise and careful machining of these components, however, generally is more expensive and requires significant quality control and review to ensure that such parts are precisely machined to within specific, narrow ranges of tolerances necessary to provide a smooth interface and function.
Accordingly, it can be seen that a need exists for a new hammer/sear interface for hammer driven firearm trigger assemblies that addresses the foregoing and other related and unrelated problems in the art.